1. Field of the Invention
The present invention relates generally to a small gas turbine engine, and more specifically to a lubricated bearing for the small gas turbine engine.
2. Description of the Related Art Including Information, Disclosed Under 37 CFR 1.97 and 1.98
A small gas turbine engine is used to power a small UAV (unmanned aero vehicle) because of the engine's high efficiency. The UAV can have much longer hover times because of the higher efficient gas turbine engine. Prior art UAVs are powered by small internal combustion engines or small single spool gas turbine engines.
The size and weight of the power plant used for a UAV is critical. Extra weight or space due to a larger engine reduces the space available for fuel. Less fuel results in lower hover times. Another issue to be addressed in a UAV is the shelf life of the engine or other parts that are required to fly the UAV. A military UAV must have a very long shelf life in order to be used by the military. Thus, liquids such as lubricants must be capable of being stored for these long shelf lives if the UAV is to be operated. Modern aero gas turbine engines include a bearing lubrication system that can form up to 17% of the weight of the engine. Prior art bearing lubrication systems includes parts like lubricant reservoir, pump, lubricant cooling system, and the necessary piping to deliver and collect the lubricant to cool the bearings. These parts add to the weight of the engine.
What is needed is a bearing lubrication system for a small gas turbine engine that will provide for a long shelf life, reduce the complexity and weight of the engine, and provide adequate lubrication and cooling for the bearing during engine use.